Dec 16, 2004 - The authors would like to thank Dr David Lindenmayer, Professor Hugh Possingham, members of the 'Reimagining the ...... (O'Connor 1990) ...
Biodiversity Author: Steven Cork, Land & Water Australia and CSIRO Paul Sattler, Paul Sattler Eco-consulting Pty Ltd Jason Alexandra, Alexandra and Associates Pty Ltd
Peer reviewers: Dr D Lindenmayer, Centre for Resource and Environmental Studies, ANU Dr D Lunney, Department of Environment and Conservation, NSW Professor H Possingham, University of Queensland Dr John Woinarski, NT Department of Infrastructure Planning and Environment
Citation: Cork S, Sattler P and Alexandra J 2006, ‘Biodiversity’ theme commentary prepared for the 2006 Australian State of the Environment Committee, Department of the Environment and Heritage, Canberra, .
Acknowledgements The authors would like to thank Dr David Lindenmayer, Professor Hugh Possingham, members of the ‘Reimagining the Suburb’ group at RMIT University (Sarah Bekessy, Ascelin Gordon, William Langford, and Georgia Garrard), Dr Denis Saunders, Dr John Woinarski and Dr Dan Lunney for their critical reviews, comments and suggestions made on earlier drafts of this commentary.
Executive summary Despite large investments and some promising responses, biodiversity in Australia continues to decline. Because of ongoing pressures and the legacy of past pressures, we cannot expect to see major reversals in this decline in the near future. This is the third national state of the environment report that raises concerns about the lack of long-term, systematic biodiversity information that would allow firm conclusions to be drawn about the details and mechanisms of this decline and, especially, whether responses are being effective or are likely to be effective. Australia’s biodiversity is of incalculable value to this and future generations. As well as underpinning the culture of Australian society, it provides raw materials (for example, water, fibre, food products, chemicals) and services (for example, water filtration, pest control, waste disposal, stabilisation of waterways and coasts, regulation of air quality) that support industries as diverse as tourism, forestry, agriculture, fishing, boat building, manufacturing, human life and wellbeing in general. Data on the relative strength of pressures on biodiversity, changes in the number and status of species, and the effectiveness of responses are too patchy in geographic spread and too narrowly focused on a few pressures, species or responses. Data are also not systematic enough to allow firm conclusions to be drawn about changes from one state of the environment reporting period (1997, 2001, 2006) to the next at a national scale. A greater commitment to long-term ecological research and strategic monitoring of key biodiversity indicators is required to allow assessments of change over these time scales. Some broad conclusions can, however, be made about trends operating over a longer time frame. It is clear that the major pressures on biodiversity that have been operating for decades are still strong and will continue to drive decline in biodiversity across large areas of the continent, together with new and emerging pressures. Some responses to biodiversity decline are beginning to have effect and promise to provide substantial future benefits. Involvement of people from across Australian society in actions to conserve biodiversity is providing important human and financial resources. A wide range of experts across Australia identify some of the major pressures that threaten biodiversity on a national scale (not in order of significance) to be: total grazing pressure, weeds, invasive organisms, changed fire regimes, and habitat fragmentation. For example, grazing and the conversion of pastures to support it have reduced the extent of native grasslands in a range of temperate Australian ecosystems to less than two per cent of that present in 1750 and have simplified the structure and quality of habitat for animals in these systems. As of 2004, a total of 95 species of animals and 68 plants were listed under the Environmental Protection and Biodiversity Conservation Act 1999 (EPBC Act) as threatened by at least one invasive organism and it is estimated that Australia gains around 20 new pests
or diseases each year; and major habitat changes have occurred in both northern and southern Australia due to changed fire regimes, especially with widespread drought conditions in recent years. Other pressures are of particular significance in some regions. These include vegetation clearing, pollution of waterways by nutrient enrichment, changed hydrology, and salinity, which are of concern both because of their direct effects and their interaction with other pressures. These major pressures are interrelated and operate over a range of scales, from local to regional to national. They have been operating over long periods of time, resulting from patterns of economic development, population growth in Australia, and global processes like increased movement of species within and between countries. The pressures have a legacy (often called an ‘extinction debt’) that will continue for decades to come, even as Australia takes remedial action. Notably, vegetation clearing may become a less significant direct threat in the future. Most states and territories have now introduced legislation aimed at regulating broadacre vegetation clearing, but the legacies of past vegetation clearing—including changed hydrology, habitat loss and fragmentation, and impacts on seed supplies and regeneration of native vegetation—remain strong drivers of biodiversity decline. Climate change will further compound and intensify pressures on biodiversity, especially by affecting rainfall patterns, and hence fire frequency, affecting regeneration of vegetation, and changing where plants and animals can live. Different pressures are more or less important in different parts of Australia. Minimising their impacts will require improved knowledge and strategic action tailored to each part of the continent. Notable recent responses to pressures on biodiversity include: major policy reforms intended to phase out broadscale vegetation clearing, and commitments to providing environmental flows for some rivers and wetlands. These reforms should make significant contributions to protecting Australia’s biodiversity in the future. Significant investment has been made through the Natural Heritage Trust (NHT) and the National Action Plan for Salinity and Water Quality (NAP). Funding of regional projects through these programmes resulted in increased awareness, interest, and community involvement in biodiversity conservation. Detailed evaluations of the effectiveness of these ambitious programmes are not yet available. Because responses are dispersed between all tiers of government, regional organisations, communities and industries, coordination, measuring of biodiversity outcomes, and identifying which actions were or were not successful remain major challenges. National objectives and targets for biodiversity conservation have been agreed by all states and territories other than Queensland, Tasmania and the Northern Territory. The only major review available on progress towards these targets (Griffin NRM Pty 2004) concluded that
progress was encouraging on only 38 per cent of the 29 targets which were mostly policy, regulatory or planning process targets rather than biodiversity outcome targets. Effective management of biodiversity in Australia requires an improved capacity to collect, synthesise and interpret key information and to consider biodiversity in the context of broader environmental change. Planning effective management responses requires a commitment to significant increases in research on understanding and measuring biodiversity and its roles in ecosystem function, mapping of vegetation and ecosystems at appropriate scales, and development and implementation of monitoring frameworks at a range of scales (regional, state and national). Monitoring should directly lead to adaptive management and be incorporated into an experimental learning framework that tells us how different strategies perform. The National Land and Water Resources Audit’s Australian Terrestrial Biodiversity Assessment (NLWRA 2002) provided an important review of information and trends related to various elements of biodiversity at a bioregional scale across the continent. There is a need for ongoing collection and dissemination of this type of information to allow assessment of progress in biodiversity conservation and to support strategic interventions to protect biodiversity. Many responses to biodiversity decline have been reactive. In some bioregions—particularly those subjected to intense development for urbanisation or agriculture—major programmes of ecosystem restoration are required. Restoration programmes need to be planned carefully and based on best available science, to deliver multiple biodiversity and other natural resource benefits. Prevention is more cost effective than restoration, and proactive and anticipatory policies are required that focus on preventing ecosystem and species decline. Australia’s terrestrial protected area system is a central strategy in protecting biodiversity and, while it has increased to cover about 10.5 per cent of the continent, it is not representative across bioregions. Specific effort is needed to meet commitments to develop a fully representative system across all bioregions where the opportunity remains. As knowledge of Australia’s ecosystems improves so does the understanding of the scale of the pressures and the challenges for responding to those challenges. The authors believe that implementation of programmes across the broader landscape has not been sufficiently proactive, strategic or adequately resourced to address the accumulating impacts that are driving biodiversity decline. Stemming biodiversity decline will require biodiversity initiatives in which detailed responses are tailored to each bioregion of Australia and are sufficiently understood to focus the current investment in regional delivery processes. A basic platform of knowledge and community commitment now exists to develop such initiatives.
Introduction We should be cautious when generalising about the condition of Australia’s biodiversity, because it includes a huge variety of micro-organisms, fungi, plants, and animals (Table 1), their genes and the ecosystems that they are part of. While some species tend to decline due to the activities of humans, others benefit and even thrive in human-modified environments. Increases or declines outside the bounds of natural fluctuations are of concern, and it is difficult to establish those bounds without long-term ecological research. Conclusions based on a few conspicuous species can lead to misleading conclusions. Australia’s biodiversity reflects 300 million years of evolution separated from the rest of the world, 60 000 years of human occupation, and the impacts and achievements of the past 200 years (Keating and Harle 2004). The unique biodiversity of this ancient continent is important for at least four reasons. Firstly, biodiversity, together with non-living components of ecosystems such as soil and water, generates the processes and delivers the services that enable humans and all higher life forms to exist. Secondly, ethical principles dictate that all species have a right to exist, and that future generations have the right to enjoy a similar quality of life and choices as present generations. Thirdly, Australians gain aesthetic and cultural benefits, such as a sense of place and identity and spiritual connections, from landscapes rich in biodiversity (see Tacey 1995). Fourthly, biodiversity and its role in functioning ecosystems support much of Australia’s economic prosperity directly and indirectly. One example is the expenditure on land-based tourism and recreation, with links to biodiversity at a range of scales. Table 1: Estimates for the total number of native species in Australia (the number in brackets is the figure that was reported in 2001) Taxon
Estimated number of species described
Estimated total number of species
Per cent endemic to Australia
Mammals
378 (369)
~378 (~369)
83%
Birds
828 (825)
~828 (~825)
45%
Reptiles
869 (633)
~900 (~633)
89%
Amphibia
219 (176)
~220 (~176)
93%
Fishes
4 500 (4 150)
~5 250 (~5 250)
90%
Agnatha
5 (5)
~10 (~10)
40%
Cephalochordata
8 (8)
~8 (~8)
50%
Tunicata
754 (536)
~850 (735)
25 – 30%
Total vertebrates
7 561
~8 444
79%
Vertebrates
Invertebrates
Taxon
Estimated number of species described
Estimated total number of species
Per cent endemic to Australia
Hemichordata
17
22
25 – 30%
Echinodermata
1 165 (1 206)
~1 406 (~1 400)
31%
Insecta
~80 000 (58 532)
~95 000 – 204 743 (~83 860)
unknown
Arachnida
5 711 (5 666)
~27 960 (~27 960)
unknown
Myriapoda
405
~2 800
unknown
Crustacea
7 130 (6 426)
~9 500 (~9 500)
unknown
Onychophora
71 (56)
~80 (~56)
unknown
Mollusca
~8 700 (9 336)
~12 250 (~12 250)
38%
Annelida
2 300 (2 125)
~4 230 (~4 230)
67%
Nematoda
~2 060 (2 060)
~30 000 (30 000)
unknown
Acanthocephala
56 (57)
~160 (~160)
unknown
Platyhelminthes
1 593 (1 506)
~10 000 (~10 800)
unknown
Cnidaria
1 705 (1 270)
~2 200 (~1 760)
unknown
Porifera
1 416 (1 416)
~3 500 (~3 500)
56%
Others
2 213 (2 929)
~5 015 (~7 230)
unknown
Total invertebrates (rounded)
114 600
~250 000
unknown
1 852 (1 500)
~2 200 (~2 500)
25%
18 140 (15 638)
~20 500 (20 000 to 25 000)
90%
Ferns and allies
(446)
(~500)
(40%)
Gymnosperms
(113)
(unknown)
(96%)
Magnoliophyta
(17 580)
(19 000 to 21 000)
(91%)
Total plants
~20 000
23 000
84%
3 227 (2 877)
~5 000 (~5 000)
34%
5 672 (12 500)
160 000 to 250 000 (250 000)
90%
Bacteria
~40 (unknown)
40 000 (unknown)
unknown
Cyanophyta
~40
12 000 – 40 000
unknown
Plants Bryophyta Vascular Plants
Others Lichens Fungi
Taxon
Estimated number of species described
Estimated total number of species
Per cent endemic to Australia
Algae
~10 000 (5 000)
12 000+ (10 000 to 12 000)
unknown
Viruses
~400
unknown
unknown
Protoctista
~10 000 (unknown)
~65 000 (unknown)
unknown
Total other
~30 000
300 000 – 400 000
unknown
Vertebrates
7 558
~8 444
79%
Invertebrates
114 600
250 000
unknown
Plants
20 000
23 000
84%
Others
~30 000
300 000 – 400 000
unknown
Grand total
172 200 (139 664)
All Species
580 000 – 680 000 unknown (745 000) Source: Chapman (in press)
Monitoring and reporting on biodiversity—state of the environment reporting Australia is committed to biodiversity conservation as a signatory of the 1992 International Convention on Biodiversity. It is also committed to independent state of the environment reporting as specified by legislation pursuant to the Environmental Protection and Biodiversity Conservation (EPBC) Act 1999. Managing and reporting on biodiversity requires knowledge of its roles, value and importance; its condition; the pressures on it; changes resulting from pressures; and the appropriateness and effectiveness of policy and management responses. Australia’s capacity to comprehensively make these assessments remains poor, but there is ample evidence of major systemic pressures on biodiversity causing undesirable and sometimes dire impacts. The 1996 state of the environment report (SoE1996) outlined more than 50 issues of concern for biodiversity conservation (Saunders at al. 1996). The 2001 biodiversity theme report used 65 environmental indicators to define the nature of environmental issues, identify solutions, and track progress towards these goals (Williams et al 2001). The 2006 assessment has been undertaken with reference to a smaller set of broad indicators that incorporate many aspects of the earlier indicators. Data and some interpretation relating to these indicators have been provided through an Internet data reporting system . The SoE 2001 biodiversity theme report (Williams et al 2001, p. 22) observed:
In order to track these changes, a monitoring program is essential where repeated sets of measurements are compared with a benchmark set or condition. For SoE reporting, these benchmarks must enable the effects of current programmes and policies and of land/resource management activities to be assessed in relation to their biodiversity outcomes.
Such an ecological monitoring programme still does not exist. In its absence, and with indicators changing from one state of the environment report to the next, it is not possible to draw firm conclusions about changes in the state of biodiversity from one reporting period to the next. Monitoring should not, however, be considered an end in itself. Its role is in achieving goals such as better management decisions, early warning, progress against targets and milestones, learning, and community education. Ideally, monitoring of biodiversity should be incorporated into an experimental learning framework that tells us how different strategies perform and leads to better solutions (Possingham 2000; Possingham at al. 2001).
The pressure, state, response model This report is structured around the three elements of state of the environment reporting: pressures on biodiversity, the impacts of those pressures on the state of biodiversity, and responses to the pressures. For clarity, and in response to reviewer’s comments, most discussion of responses is in a separate section but pressure-specific responses are also referred to in the relevant subsection of ‘Pressures’.
Information used in this report In this report, a range of information relating to condition and trends in Australian biodiversity is considered, especially information that has become available since the 1996 SoE report and the 2001 SoE biodiversity theme report (Saunders at al. 1996; Williams at al. 2001). Most of that information is summarised in the data reporting system and only selected highlights are reported in detail in this commentary. One of the sources of information in the period since SoE2001 has been the Australian Terrestrial Biodiversity Assessment (NLWRA 2002), which is the most comprehensive national collation and interpretation of information undertaken to date. Its conclusions were drawn after SoE2001 was completed. Most of the other information that has become available since SoE2001 is of limited geographic spread or focuses on a limited range of issues.
Summary of indicator trends Table 2 summarises the indicators used and the key issues for biodiversity. This commentary does not attempt to comment in detail on each indicator. The key pressures are similar to those identified in earlier reports, although the impact of some are likely to decrease due to policy responses (for example, vegetation clearing controls being introduced and implemented in most states and territories), while pressures of others have increased (for example, the number or extent of invasive species), and some are now recognised as more
important than previously thought (for example, climate change). As explained above, detailed conclusions about changes in most indicators between state of the environment reporting periods are not possible. Similarly, conclusions about the relative importance of individual pressures (apart from identifying the major group of pressures discussed above) are not warranted because their importance can vary between locations and because the pressures are interrelated and need to be addressed together rather than separately. Table 2: Summary of this commentary on biodiversity indicators Issue (and indicators)
Comments
Utilisation and value of biodiversity It has been well established that Australian biodiversity has major economic and broader values to Australians and the world, although there is debate about how to measure these values precisely. Benefits such as carbon sequestration, water filtration, pest control, and maintenance of air quality are not currently quantified in economic or other terms and yet they are among the most valuable aspects of utilising biodiversity. Harvesting and trade in wildlife •
Australian fisheries production - National Tonnage and Value of Retained Catch Average tonnage and value of other (nonfood) agricultural products per hectare of land under production
•
Ecologically sustainable harvesting of some selected nationally significant native species
Research and monitoring of some commercially harvested species suggest that, with appropriate science-based management, direct use of native species can be managed sustainably. Cases of sustainable use supported by sufficient research and monitoring are rare.
Medicines and other potentially useful biological compounds •
Number of compounds from terrestrial sources at some stage of commercial development
•
Number of compounds from coastal and marine sources at some stage of commercial development
Incentives for biodiversity management •
Government investments to protect biodiversity for public good purposes
Tourism •
Tourism activities based in areas of high biodiversity significance
•
Value of and numbers participating in landscape based tourism and recreation
•
Value of an numbers participating in coastal and marine based tourism and recreation
•
Number of international and domestic tourists
No data are available.
Many catchment management authorities and local and state governments are beginning to deliver an increasingly wide range of incentives that are intended to conserve biodiversity through improved management of habitats. These schemes are small relative to the extent of degradation and the level required to reward biodiversity stewardship. Nature-based tourism continues to be a significant component of Australia’s economy, but this is often not reflected in the level of management resources provided to conservation agencies to protect biodiversity values in parks. Apart from a few examples like the Great Barrier Reef, the tourism industry makes little direct contribution to management of, and research into, the biodiversity infrastructure on which it fundamentally relies. This is an opportunity to improve both funding for biodiversity assessment and recognition of the economic value of biodiversity
Pressures on biodiversity Land clearing •
Change in area and proportion of woody native vegetation
Invasive organisms •
Current research into pressures and contributions of naturalised introduced species
•
The change in extent of selected nationally significant introduced invasive organisms
•
Examples of native species whose populations have declined where various invasive organisms have established resident populations
•
Land use and land use change
•
Examples of significant wetland weeds
•
Examples of carp pressures and measures for removal and/or commercial catch
•
Correlation between various human activities and introduction of coastal and marine species
Rates of broadscale land clearing are expected to decline nationally (at different rates in different states and territories) due to new regulations on land clearing. However, loss of remnants, fragmentation and clearing of regrowth in key areas is a major ongoing issue. Effective implementation of recent legislative reforms is important. There has been increased attention in the literature to impacts of invasive organisms since 2001. Invasive organisms are, or are likely to become, a major threat for many species and ecosystems. Developments include an increased focus on controlling the entry of new species. A number of legislative and policy gaps have been identified and addressed. Nevertheless, the spread of introduced pasture species (including invasive pasture grasses) is still a major concern with few solutions in sight. With respect to aquatic systems, there is a rise in naturalised freshwater fish nationally.
Fire •
Area burnt by frequency, intensity and season of burning
•
Examples of the impact of fires on biodiversity
•
Temporal and spatial correlation between changing fire regimes and species change
•
Severe drought and wildfire correlation
Grazing pressure •
Examples of the impact of grazing on biodiversity
•
Total grazing pressure relative to net primary productivity
Changed hydrology •
Examples of the impact of changed hydrology on biodiversity
•
Area and proportion of land affected by or at risk of dryland salinity and acidity
•
Average annual groundwater depth
•
Groundwater management plans that consider groundwater dependent ecosystems
While increased attention has been given to fire as a pressure on biodiversity since SoE1996 and SoE2001, the data still do not allow conclusions to be reached about changes in fire regimes nationally. In parts of Australia, including the northern savannas, the scale, frequency and intensity of fires remains a key issue for biodiversity. Fires in southern Australia tend to be more episodic, with large-scale fires like the 2003 alpine fires favoured by periods of below average dryness. There is still no serious system of fire mapping and fire regime mapping in Australia. This is needed for such a fire-prone continent (Cary et al 2003)
Total grazing pressure is one of the most significant issues for biodiversity conservation. Grazing not only leads to removal of vegetation and, often, soil degradation, but also on the quality of habitat as overgrazing simplifies the structure and complexity of vegetation. Impacts are likely to increase as average climate and climate variability change. Ongoing expansion of watering facilities in some areas is a major driver of total grazing pressure. The extent of water remote lands in rangelands could be a useful indicator. Changed hydrology remains a major pressure, especially since the full effects of salinity from historical vegetation clearing have yet to be realised. Increasing direct effects on wetlands and aquatic dependent biodiversity are likely to be made worse with climate change. Inadequate attention has been paid to groundwater-dependent biodiversity. Considerable planning is required to address restoration at broad landscape scales.
Climate variability •
Examples of impacts of climate variability on selected terrestrial species, habitats or ecosystems
•
Examples of the impact of climate variability on selected coastal and marine species, habitats or ecosystems
Climate change, including associated change in the variability of climate, ranks with habitat modification as the biggest global threat to biodiversity (Thomas et al 2004; Millennium Ecosystem Assessment 2005a, b). In Australia, changes in average climate and climate variability are being recognised as among the most significant emerging threats. There are few long-term datasets to test impacts and develop predictions. Discerning the effects of climate variability from other pressures in the past is an issue. Efforts to reduce climatic pressures are long-term, expensive and multi-national. Mitigation of impacts will need a new focus on ecosystem management and must consider the capacity of genes, species and ecosystems to adapt to change. Future mitigation plans should consider the possibility that extreme measures, such as active translocation of species to new habitat, might be needed.
Species, habitats and ecological communities Species diversity •
The number of fauna and flora species described in Australia compared with previous years and estimated total number of species
Conservation status of species and ecological communities •
Conservation status of nationally significant species and ecological communities, compared with previous years
ABRS estimates that around 172 200 species have been described (this figure was 139 664 in SoE2001) of an estimated total of 580 000 to 680 000 (was 745 000 in SoE2001). Because this is only 25 per cent (compared with 19 per cent in 2001), this indicator does not currently say much about the diversity or state of Australian biodiversity. It does, however, provide important information on taxonomic effort.
Since the commencement of the EPBC Act in 2000, there have been 134 species and ten ecological communities added to the original lists of threatened species and threatened ecological communities. This does not include transfers to other categories on the list or species that have been delisted. Changes to these lists are essentially in response to public nominations from parties with an interest in a particular species or ecological community. It is not a systematic assessment of species most at risk. Therefore these lists cannot be used as an accurate indicator of biodiversity change. Using similar criteria, but using available data for all ecosystems across Australia, the NLWRA identified over 2800 threatened ecosystems.
Condition of wetlands and riparian vegetation •
Extent of significant wetlands
•
Examples of deterioration of condition of wetland vegetation
•
Ramsar wetlands with implemented management plans
Government action on species and ecological communities conservation or management
The good condition of many rivers in northern Australia is an asset worthy of note and protection.
While the date reporting system shows increases in funding for some aspects of threat abatement for invasive organisms, the effectiveness of funded projects is unknown. The few data available on trends in species targeted by recovery plans suggests mixed success.
•
Summary of measures being implemented to respond to threats to biodiversity from invasive species
•
Listed threatened species or ecological communities for which recovery action is showing stable or increasing populations
There has been an increase in the number of species listed under Australian government legislation as vulnerable, endangered or critically endangered for all groups, but this mainly reflects listing activity and cannot be linked to changes in the status of biodiversity. Conservation effort should also focus on non-threatened species and ecosystems such as the conservation of endemic species.
•
Alignment of state, territory and Australian government listing processes
Progress has been made recently on aligning listing between the Australian Government and the states and territories (see ).
Community action on species and ecological communities conservation or management •
Measures taken to conserve species or ecological communities on land that is not part of the national reserve system
•
Indigenous knowledge of species and ecological communities and their utilisation for management by Indigenous and nonIndigenous managers and for other purposes by Indigenous and non-Indigenous people
There is a trend towards greater community involvement in biodiversity planning and management, with assistance from governments, but the effectiveness of this involvement has not been evaluated in most cases. It is important to avoid the establishment of a system of ‘paper’ protected areas on private lands without effective monitoring tied to adaptive management.
Case studies reviewed in the data reporting system suggest that the use of Indigenous knowledge can have benefit to the whole community, but there are no data on trends in efforts to capture and use indigenous knowledge. The 2006 Australian State of the Environment Committee commissioned four case studies on Indigenous involvement in environmental management (see ).
Landscapes Ecosystem diversity •
The proportion and area of native woody and non-woody vegetation and changes over time
•
Change in extent and proportion of woody vegetation, clearing and regrowth
•
Fragmentation of remnant vegetation
•
Estimated loss of biodiversity resulting from land clearing
•
Conservation status of nationally significant species and ecological communities, compared with previous years
•
Trends in selected groups of coastal and marine species and habitats
Most available data relate to broad vegetation types. The proportion of 1750 extent remaining varies from 63 to 100 per cent. This masks major declines in particular species and assemblages within these major types, declines in condition of the vegetation as habitat, decline in connectivity of habitat and much higher than average rates of clearance in some regions and bioregions, all of which have major implications for biodiversity. One of the major concerns is lack of replacement of old with young plants in largely cleared landscapes. More than 17 million hectares of forest have been cleared nationally since 1973. Taking account of revegetation and regrowth, the net loss was about 7.5 million hectares. There are major limitations to drawing conclusions about the impacts of vegetation clearance on biodiversity because there are few nationwide data on vegetation extent and condition, and there is no comprehensive mapping of vegetation ecosystems at an acceptable planning scale of 1:100 000 to 1:250 000 across Australia. Land clearing in Australia is expected to decline in the future due to new regulations in all states and territories, but this is not apparent in the data available for this assessment. Clearing in Queensland continues at a high level as part of phase-out arrangements. Revegetation programmes need to be carefully targeted to achieve defined biodiversity objectives in each locality. The total nett loss of forest in Australia due to land clearing between 1973 and 2004 was about 7.5 million hectares. Data on forest regrowth presented in the data reporting system are difficult to interpret and potentially misleading. It is not clear what the nature of much of the regrowth is—a large proportion is likely to be non-native and of low value for biodiversity. Revegetated and regrowth areas do not necessarily have the same habitat qualities as the previous vegetation. Revegetation strategies should include strategies to reward protection of natural regrowth in key areas. There is declining condition in vegetation and lack of recruitment in many extensively cleared landscapes.
Government action on landscape protection
Significant vegetation management reforms have occurred and are being implemented in Queensland, New South Wales and Tasmania since SoE2001.
•
Extent and comprehensiveness of terrestrial protected areas
•
Number and extent of marine protected areas
A comprehensive protected area system across all bioregions has not been met. Approximately, 67 per cent of regional ecosystems are represented in national parks and similar reserves. Opportunities for a representative system of protected areas are non-existent in some bioregions and diminishing in others.
•
Institutional response to loss of native vegetation
The effectiveness and efficiency of major national initiatives through the Natural Heritage Trust (NHT) and the National Action Plan for Salinity and Water Quality (NAP) for the protection of biodiversity at the scale required is uncertain. Limited monitoring of real biodiversity gains (as distinct from auditing process) is a major problem. The lack of integrated regional biodiversity strategies for input into a wide range of planning and delivery processes is of concern.
Utilisation and value of biodiversity Biodiversity is enormously valuable in its own right, in economic and cultural terms, and in the provision of market and non-market ecosystem goods and services (see Williams et al 2001; PMSEIC 2002; Millennium Ecosystem Assessment 2003; CSIRO 2005; BDAC 2005). Biodiversity underpins the life support systems that we depend upon. When it is lost, ecosystems break down and essential ecosystem services falter, causing economical and cultural impoverishment of societies. This can be seen today in some of the worn-out pastoral areas or salinity-affected agricultural regions of Australia. Biodiversity supplies a pool of biological and genetic resources that contribute to resilience in ecological, social and economic systems. In ecological systems, biodiversity provides ‘insurance’ against change by maintaining a range of species that perform the same or similar functions but that could adapt differently to changing conditions (Folke et al 2002). Biodiversity’s contribution to social and economic resilience is exemplified by disease resistant crops and new crop plants, such as wattle seeds for protein, plantation eucalypts, new medicines, insecticides and other products (Folke et al 2002; Elmqvist 2003; Simpson and Chudleigh 2003; Resilience Alliance 2006).
The SoE 2001 biodiversity theme report mentioned efforts to estimate the economic value of biodiversity and ecosystem services (Williams et al 2001). Such approaches are rarely integrated into decision-making processes. This is a major deficiency in current investment in biodiversity management, especially because the size of this investment is partly determined by the balance between poorly defined (and typically longer-term) benefits from conservation and well-defined (but typically shorter-term) benefits from land conversion. The indicators of utilisation and value of biodiversity for which data have been collected capture only a small part of the value and utility of biodiversity to Australians. Native species are the basis of the wild-catch fisheries, some aquaculture, native timber harvesting and many traditional food, fibre, art and craft material and medicines used by Indigenous peoples, particularly in more remote parts of Australia. The latter have considerable cultural and economic value that is rarely quantified or considered in decision-making (see Whitehead 2002). Similarly, there is little information on the economic value of biodiversity for medicine and other biological compounds, although there is increasing investment in the bioprospecting of Australia’s biological resources (see Bioprospect Limited 2006). The ongoing commercial harvesting of species like kangaroos (Table 3) and some marine fisheries such as the Western Australian Rock Lobster (Genus species) demonstrate the essential role of biological research and population monitoring in the management of species harvested commercially. Table 3: Kangaroos killed under commercial harvest quotas, 1991–2003 Year
Macropus rufus (Red Kangaroo)
M. giganteus (Eastern Grey)
1991
1 365 716
1 270 877 158 213
113 791
4 226
2 912 823
1992
1 308 140
1 183 681 182 814
139 943
2 071
2 816 649
1993
1 319 693
1 273 922 207 397
172 449
2 737
2 976 198
1994
1 425 553
1 328 561 311 504
225 644
1 965
3 293 227
1995
1 435 614
1 306 747 301 405
214 916
1 766
3 260 448
1996
1 447 698
1 066 364 353 650
232 502
909
3 101 123
1997
1 171 300
704 137
264 656
148 803
791
2 289 687
1998
1 344 214
800 707
242 630
204 789
217
149
70
2 592 776
1999
1 278 469
925 946
240 727
152 782
1 279
421
515
2 600 139
2000
1 173 242
1 106 208 227 552
238 439
357
584
20
2 746 402
2001
1 364 682
1 438 280 283 332
296 805
256
6 884
2 020
3 392 259
M. robustus M. parryi M. (Whiptail fuliginosus (Euro / Wallaby) (Western Wallaroo) Grey)
Macropus rufogriseus (Bennetts Wallaby)
Thylogale Total billardierii (Tasmanian Pademelon
2002
1 500 588
1 810 426 330 372
257 140
190
4 392
2 169
3 905 277
2003
1 121 724
1 758 173 246 672
347 914
0
0
0
3 474 483
35 616
0
0
0
1 175 699
2005 Commercial kangaroo harvest quotas NSW
445 300
550 820
143 963
Qld
472 332
1 081 340 0
338 279
0
0
0
1 891 951
SA
237 600
0
97 900
76 400
0
0
0
411 900
WA
250 000
0
180 000
0
0
0
0
430 000
Total
1 405 232
1 632 160 421 863
450 295
0
0
0
3 909 550
Source: DEH (2004a)
Nature-based tourism provides great benefit to Australia’s economy. It is recognised internationally that it is difficult for the tourism industry, which is dispersed and consists mainly of small to medium enterprises, to invest sufficiently to protect the natural resources that support this tourism industry (Keller 2005). Although few data are available, the same is probably true in Australia. Wider monitoring of pressure from tourism and the effectiveness of management responses, particularly in ecological terms on protected areas, is needed.
Pressures on biodiversity The major pressures Climate change and habitat modification are the leading drivers of biodiversity decline worldwide (Thomas et al 2004; Millennium Ecosystem Assessment 2005a, b). In Australia, climate change will be one of the major pressures on biodiversity in the next few decades. Direct habitat loss through vegetation clearing is expected to decrease due to legislation to curtail it in most states and territories, but the remaining pressures are powerful: the legacy of past clearing together with the direct impacts on habitat and native species of total grazing pressure, altered fire regimes, and introduced species. There are few systematic and quantitative data on trends in any of these pressures at a national scale, but the weight of evidence about their effects makes it clear that they are still having substantial impacts on a wide range of biodiversity. In the absence of quantitative data, one way to gauge which pressures are most significant nationally is expert opinion. In NLWRA (2002), which assembled information and opinion from more than 40 of Australia’s leading ecologists and experienced conservation managers, the five most frequently recorded threatening processes perceived to be pressures on a range of biodiversity assets assessed across all bioregions and subregions were:
•
total grazing pressure
•
weeds
•
feral animals
•
changed fire regime
•
habitat fragmentation.
Other less frequently reported pressures include: •
vegetation clearing (particularly eastern Australia)
•
changed hydrology and salinity (changed flows, increases or decreases in ground water)
•
pollution (including sediment and nutrient pollution of rivers, wetlands, estuaries and coastal waters).
Table 4: Expert opinions on the ranking of threats to several aspects of biodiversity (from Tait, unpublished report, drawing on NLWRA 2002) Threatened Species (see caption for difference between columns)* Feral animals Changed fire regimes
Vegetation clearing Grazing pressure
Grazing pressure
Feral animals
Exotic weeds
Changed fire regimes
Other Increasing fragmentation Vegetation clearing Changed hydrology Pollution Pathogens
Increasing fragmentation Changed hydrology
Threatened Ecosystems
Riparian Zones
DIWA wetlands
Grazing pressure
Grazing pressure
Grazing pressure
Exotic weeds
Exotic weeds
Feral animals
Feral animals
Changed hydrology
Changed hydrology
Increasing fragmentation
Pollution
Feral animals Exotic weeds Changed fire regimes Increasing fragmentation Vegetation clearing
Exotic weeds
Changed hydrology
Pollution
Salinity
Salinity
Firewood collection
Salinity
Changed fire regimes
Firewood collection Salinity * For columns 1, 3, 4 and 5 the ranking was based on the number of IBRA subregions reporting the threat. For column 2 the ranking was based on numbers of species per subregion reported to be threatened; DIWA = Directory of Important Wetlands in Australia
These pressures have greater impacts in Australia, compared with other parts of the world, for several reasons: •
Australia has experienced high rates of recent land use change, with approximately half of all clearing and land development for agriculture occurring in the last 30 years (Dunlop et al 2002; Dunlop 2003). This has altered the extent, quality and patterns of habitat and changed fundamental hydrological and other processes
•
Australia has high rates of diversity and endemism, with many plants and animals adapted to specific climates: many species could face challenges adapting to expected climate change
•
Australian biodiversity is adapted to fluctuating patterns of fire frequency and intensity, and water availability, both of which are being altered by human activities;
•
Altered erosion rates and nutrient status of soil and water systems are impacting on plants and animals adapted to this continent’s old and nutrient-poor soils and on species adapted to low nutrient riverine, estuarine and coastal ecosystems
•
Australia, with its 300 million years of geographic isolation and separate evolution, has been protected from biotic invasions. It is increasingly being exposed to exotic species due to increased globalisation of trade and movement of people.
In the following section, comment is made on these major pressures individually, but it should be born in mind that they are not independent. They often interact to increase one another’s impact, and they should not be dealt with individually. This is why landscape-scale responses to biodiversity decline, discussed later, are extremely important.
Land clearing Recognition of the impact of clearing Australia's native vegetation is not new. As long ago as 1892, Samuel Dixon expressed concern to the Royal Society of South Australia (Dixon 1892) about the destruction of the forests, balding of hills, increased flooding and loss of indigenous flora. The clearing of native vegetation has been recognised as one of the biggest threats to Australia’s biodiversity in previous state of the environment theme reports (Saunders et al 1996; Williams et al 2001). Since SoE2001, significant reforms to vegetation management have occurred in Queensland, New South Wales and, very recently, Tasmania (Table 5). Table 5: Native vegetation reform commitments in NHT and NAP bilateral agreements Jurisdiction
Reforms
Australian Capital Territory
Stronger emphasis on biodiversity and vegetation management through land management agreements on all rural leases
New South Wales
Commitment to end broadscale clearing and clearing of protected regrowth vegetation
Northern Territory
Commitment to control the clearing of native vegetation across all tenures
Queensland
Commitment to protect all threatened vegetation communities and phase out clearing of remnant vegetation by 2006
South Australia
Commitment to achieve a net gain in native vegetation quality and extent
Tasmania
Commitment to protect all threatened forest and non-forest vegetation communities and maintain at least 95 per cent of the 1996 native forest estate on public land
Victoria
Native vegetation management framework in place to achieve a net gain in native vegetation cover
Western Australia
Environmental Protection Act 1986 now protects native vegetation
Source: DEH(2004b)
The effects of these reforms are not yet evident. Declines in rates of land clearing are not evident in the data available for this assessment (see Tables 6–7 and Figures 1–4), and clearing in Queensland continues at a high level as part of a phase out programme. Overall there was a nett loss in ‘forest’ between 1973 and 2004 due to land clearing of about 7.5 million hectares. Clearing has resulted in high death rates for a range of fauna and flora species in this 2001–06 reporting period, but there has been insufficient monitoring to allow conclusions about the impacts on the long-term viability of populations. Table 6: Area of deforestation in states and territories, 2001–04 Number of hectares cleared each year State or territory
2001
2002
2003
2004
New South Wales
72 420
64 073
64 068
110 858
Northern Territory
1 325
1 510
1 718
5 751
Queensland
288 257
215 131
192 390
219 961
South Australia
9 929
8 438
8 064
12 329
Tasmania
7 369
10 432
12 260
13 717
Victoria
10 454
13 058
13 640
23 407
Western Australia
29 795
34 599
35 231
38 704
Source: ERIN (2005); International definition of forest is defined as vegetation that has at least 20 per cent canopy cover, is two metres tall and has a minimum of 0.2 hectares. It does not distinguish between native and non-native woody vegetation. The analysis includes land that has been cleared more than once during the period
Table 7: Area of forest regrowth in states and territories, 2001–04 (may include land that has been cleared more than once during the period) Number of hectares cleared each year State or territory
2001
2002
2003
2004
New South Wales
63 610
74 852
76 483
115 373
Northern Territory
4 206
5 264
6 323
9 076
Queensland
99 844
115 373
108 339
117 173
South Australia
18 465
15 517
15 419
18 636
Tasmania
12 753
12 517
12 527
11 374
Victoria
40 293
36 816
35 531
49 311
Western Australia
63 214
57 050
56 498
50 247
Source: ERIN 2005
Figure 1: Area of deforestation in Australia, by state and territory, 2001–04 (can include land that has been cleared more than once during the period)
300,000
2001
2002
2003
2004
250,000
Area (Ha)
200,000
150,000
100,000
50,000
-
NSW
NT
QLD
SA
TAS
Vic
WA
Source: ERIN 2005
Figure 2: Area of forest regrowth in Australia, by state and territory, 2001–04 (can include forest regrowth that has been cleared more than once during the period)
150,000
2001
2002
2003
Area (Ha)
100,000
50,000
-
NSW
NT
Qld
SA
Tas
Vic
WA
2004
Source: ERIN 2005
Figure 3: Net forest change in states and territories (2001–04) 600,000
Regrowth Land clearing 400,000
200,000
Area (hectares)
0
200,000
400,000
600,000
800,000
1,000,000
NSW
NT
Qld
SA
Tas
Vic
WA
Regrowth
330,318
24,869
440,729
68,037
49,171
161,951
227,009
Land clearing
311,419
10,304
915,739
38,760
43,778
60,559
138,329
Source:ERIN 2005
Figure 4: Net forest change in Australia (difference between deforestation and forest regrowth) 1973–04
800,000
Regrowth Land clearing Nett change
600,000
400,000
200,000
Area (hectares)
0
200,000
400,000
600,000
800,000
1,000,000
1,200,000 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004
Source: ERIN 2005
While recent developments may make broadacre vegetation clearing itself of less concern as a direct pressure nationally than it was at SoE2001 (although it remains a significant pressure in some parts of Australia), the legacy of past clearing is a major ongoing pressure. Once vegetation communities and their associated animals and other organisms have been fragmented and disturbed by clearing they become susceptible to other pressures such as insects, weeds, overgrazing, compaction, salinisation, and changed fire regimes (Saunders et al 1996; Williams et al 2001). In particular, changed hydrology may underlie increasing salinisation for many decades (see Murray–Darling Basin Commission 2003b). For vegetation communities, these pressures can result in a decline in health, increased susceptibility to diseases, failure of regeneration, and even plant death. As many vegetation communities on fertile soils have been preferentially and extensively cleared, these communities are generally under-represented in protected areas, and remnants outside reserves are under particular threat. Recent work in South Australia and Western Australia raises fears that direct removal of paddock trees, coupled with a lack of regeneration, will lead to a near-complete loss of paddock trees from many rural landscapes in the future (Saunders et al 2003; Carruthers and Hodder 2005). For both plants and animals, fragmentation of large areas of habitat into smaller pieces means that fewer species can be accommodated in the new ‘islands’. In addition, fragmentation can slow or prevent the mixing of genes among individuals in populations, which can result in inbreeding that reduces the reproductive fitness and long-term health of populations. It is estimated, for example, that even after cessation of clearing in the Mount Lofty Ranges of South Australia, 16 species are likely to go extinct within 200 years due to past impacts (Westphal et al 2003). Available data also report declines in a range of bird species in other parts of Australia (Olsen et al 2006) At present there are few studies of genetic fitness and health of Australia’s biodiversity, although with the increasing capacity through high-speed genetic profiling, research into genetic impacts for some species will be more feasible in coming years. Clearing in the past has been much higher in some vegetation types than others (NLWRA 2002; and also Table 8; Figure 5). In general, policy frameworks have not been in place to determine the environmental risks and costs, such as of loss of ecosystem services, of clearing in each area (for example, the loss of carbon sequestration and artesian aquifer recharge associated with clearing of marginal rangelands in the Desert Uplands of Queensland). In terms of both planning and state of the environment reporting, there is a need for better assessment processes that assess the trade-offs between development, biodiversity impacts, and implications for ecosystem services at scales relevant to the processes involved; those tradeoffs should also be made much clearer than they are now.
Table 8: Areas of estimated pre-1750 and remaining (2001–04)* vegetation in Australia (km2); percentage of remaining vegetation in reserves Estimated pre-1750 area (km2)
Area remaining (km2)
Percentage remaining
Percentage of remaining vegetation in reserves
Rainforest and vine thickets
53 469
35 200
65.8
54.4
Eucalyptus tall open forest
40 801
35 344
86.6
33.6
Eucalyptus open forest
394 280
272 121
69.0
22.7
Eucalyptus low open forest
4 726
3 952
83.6
35.1
Eucalyptus woodlands
1 362 263
892 920
65.5
8.1
Acacia forests and woodlands
495 059
408 632
82.5
8.8
Callitris forests and woodlands
40 278
32 296
80.2
6.1
Casuarina forests and woodlands
166 303
149 262
89.8
18.5
Melaleuca forests and woodlands
106 057
99 561
93.9
10.1
Other forests and woodlands
80 772
72 414
89.7
9.9
Eucalyptus open woodlands
498 663
458 905
92.0
6.2
Tropical eucalypt woodlands/grasslands
115 503
112 481
97.4
12.8
Acacia open woodlands
320 981
314 040
97.8
7.6
Mallee woodlands and shrublands
387 230
271 529
70.1
36.8
Low closed forest and tall closed shrublands
25 819
16 278
63.0
30.5
Acacia shrublands
865 845
851 274
98.3
10.0
Other shrublands
157 530
123 464
78.4
18.7
Heath
9 256
8 071
87.2
44.1
Tussock grasslands
559 850
525 888
93.9
3.0
Hummock grasslands
1 368 861
1 367 973
99.9
9.9
Major vegetation group
Other grasslands, herblands, sedgelands and rushlands
67 977
64 810
95.3
17.2
Chenopod shrublands, samphire shrubs and forblands
447 239
436 801
97.7
12.6
Mangroves
9 664
9 325
96.5
33.1
7 578 427
6 562 541
86.6
11.5
* except for the NSW component, where most data are from 1997; Sources: National Vegetation Information System (NVIS) Stage 1, Version 3.0 Major Vegetation Groups, DEH, Canberra. URL: http://www.deh.gov.au/erin/nvis/mvg/index.html; and DEH (2006) Australia’s Native Vegetation 2006, Australian Government, Canberra.
Figure 5: Proportion of estimated pre-1750 native Major Vegetation Groups (MVGs) with less than 30 per cent area remaining, per IBRA region
Large-scale restoration of habitat is required to offset the effects of past clearing and ongoing degradation of the woodlands of south-eastern and south-western Australia. Revegetation programmes have been supported by local, state and Australian governments and have been notably implemented by non-government organisations such as Landcare and Greening Australia. To assess the effectiveness of these responses, detailed data are needed to show where the actions are taking place, which vegetation and animal associations are being
targeted, how the actions affect the connectivity of habitat, how populations are responding, and how changed hydrological regimes may be restored in some locations. As emphasised elsewhere in this commentary, plans are required that identify the specific priorities for different places and different elements of biodiversity around Australia. At present, the only data available on replacement of vegetation at a national scale are very broad. These data do not distinguish between native and introduced plants; they also include plantations, with variable value for biodiversity, and woody weeds. Revegetated areas take many decades to develop structure and other elements of habitat quality required to sustain plant and animal populations. Thus, numbers of individual plants and animals do not increase as quickly in replaced vegetation as they declined during clearing. Nevertheless, recent research indicates that in landscapes that have been predominantly cleared and grazed, revegetation can have a significant impact on fauna (Lindenmayer et al 2003). Programmes to encourage the protection of regrowth in key areas remain viable opportunities to secure some threatened ecological communities and the return of vegetation to overcleared landscapes. This can be a much more cost-effective approach than replanting in some landscapes where natural regenerative capacity remains. Other effective responses involve the fencing and special management of remnants.
Invasive organisms Invasive organisms are animals, plants or diseases that have entered Australia from elsewhere, either as deliberate or accidental introductions, and many cause economic, social or environmental harm (Australian Biosecurity Group 2005). These species have diverse modes of action, routes of introduction and spread, and geographic range among invasive organisms (Reddiex et al 2004; Australian Biosecurity Group 2005;. There are more than 2800 exotic weeds, 25 mammals, 20 birds, four reptiles, 34 fish, 100–400 invasive marine species, and unknown numbers of other invertebrate species and diseases. The CSIRO estimates that Australia gains 20 new pests or diseases each year (CSIRO 2004). In Australia, exotic pests like feral cats, foxes and rabbits are considered a primary cause of past extinctions of animal species and a potent source of ongoing pressure (see Table 10). Examples include the recent arrival of the Cane Toad (Bufus marinus) in relatively undisturbed parts of the Top End, and the devastating reduction in Quoll (Dasyurus spp) numbers. The impacts of habitat alteration can be magnified by invasive organisms. The two Australia Bird Atlas surveys reviewed by Garnett et al (2002) show increases in habitat modification and the relative abundance of introduced bird species correlated with decreases in native bird abundance and distribution. The highest abundance of introduced bird species, principally
exotic species, occur in the extensively modified parts of south-east Australia and eastern Tasmania where they now make up 15 per cent of all species (NLWRA 2002). Diseases have posed threats, and will pose new threats, to both plants and animals, especially in an increasingly globalised world (Millennium Ecosystem Assessment 2005b). A prime example is the devastating impacts of Phytophthera cinnamomi on native vegetation (Australian Biosecurity Group 2005). Although there are few data on economic costs of marine and freshwater pests, invertebrates and diseases generally, the annual costs of weeds and feral vertebrates alone (more than $4 billion) outstrip the cost of dryland salinity (more than $200 million) several-fold (Agtrans Research and Dawson 2005; Australian Biosecurity Group 2005. Table 9: Annual impacts of weeds in agriculture, natural environments, and on public and Indigenous lands ($ million)
Sector
Economic activity moderate
Economic activity low
Economic activity high
Costs of control and losses in output Agriculture
3442
3927
4420
Costs of control only: no losses in output Natural environment
20
20
20
Public authorities
81
81
81
Indigenous lands
3
3
3
Commonwealth research
8
8
8
3 554
4 039
4 532
Total Source: Sinden et al (2004)
In the past, management of invasive organisms has focused on identifying the magnitude of the impacts and on control strategies for impact minimisation (for example, the Bureau of Rural Science’s vertebrate pest series). Approaches to managing invasive organisms often have been applied without attention to monitoring the effectiveness of past responses or to experimental design (Reddiex et al 2004). Since SoE2001, increased attention has been given to protecting Australia from the threat of new invasive plant species, with a focus on the routes of invasions and integrated legislation, policies, plans and processes that aim to enhance national biosecurity. A recent analysis of weed introductions concluded that ornamental horticulture (the gardening industry) exceeds all other industries in terms of introducing new plants species, including many agricultural and environmental weeds (Australian Biosecurity Group 2005).
A number of gaps in Australia’s suite of responses to invasive organisms have been identified, including: gaps in quarantine laws; inadequate early warning surveillance; mismatches between laws in different states; inadequate contingency plans for environmental weeds, pests and diseases; inadequate approaches to integrated control of agricultural and environmental pests; inadequate funding for controlling environmental invasive species; inadequate protocols to decide priorities and who pays; poor sharing of information; and lack of community awareness (Australian Biosecurity Group 2005). The deliberate spread of some aggressive introduced pasture species and the lack of protocols for their use as part of pastoral development remains a key biodiversity issue. It has been noted that public resources committed to invasive organisms appear to be small, particularly compared with expenditure on other natural resource management issues, the economic and environmental impacts of invasives compared with other issues, and the relatively high benefit-cost ratios reported from analyses of research and development on invasive organisms (Agtrans Research and Dawson 2005). The Australian, state and territory governments have commenced a major review to identify and correct strategic gaps in Australia’s response to invasive organisms. This includes development of a National Framework to Prevent and Control Invasive Species, a National Biosecurity Strategy, a revision of the National Weeds Strategy, development of a new National Pest Animal Strategy, and progress to implement the National System for the Prevention and Management of Introduced Marine Pests. In early 2005, the Australian Government agreed to remove 4000 known weeds not yet present in Australia from the permitted list under the Quarantine Proclamation 1998. Because of the costs of invasive organisms and the risks they could pose to Australia’s diversity of ecosystems, it would be prudent to go further and place the burden of proof on proponents of any new introductions, with new species planned for introduction being considered potentially invasive until proven benign.
Fire See also: Living in a land of fire ‘Burn grass’ is as ancient as time itself. The burning of country was handed down to our people from the Dreamtime. ‘Burn grass’ takes place after the wet season when the grass starts drying off. The country tells you when and where to burn. To carry out this task you must know your country (Yinirrakun—April Bright 1995). To grow flowers in Blackheath, Australia, set fire to your fields. Let flame singe the delicate dust-seeds of native shrubs. Soon they sprout, on ground bare, as if hoed. Bright petals follow,… but not one has a name that Shakespeare knew… (O’Connor 1990)
Both quotes, from widely different backgrounds, tell of fire as a natural phenomenon and its importance in the evolutionary history of Australia. Recent research confirms the conventional wisdom that different types of country and different species of plants and animals require different fire regimes. This approach is reflected in the Ecological Society of Australia’s call for informed use of fire as a management tool and in approaches adopted by the various state agencies responsible for fire. Australia’s capacity to monitor fire has increased greatly over the last decade and this is now done at a range of scales; although the data available on the incidence and intensity of fires across Australia and the areas burned (see Tables 12 and 13) do not allow national conclusions on the overall impacts on biodiversity. In 2003, there was more than 25 000 unplanned grass or bush fires in Australia that burnt more than 67 million hectares. In the five years to 2003, approximately eight per cent of the Australian land area was burnt each year; this is in contrast to the tropical savannas (north of 21degrees South) where approximately 77 per cent of the area is burnt each year. Table 10: Estimated area of unplanned fires in Australia, 2002–03 State or territory
Number of unplanned grass and forest fires
Estimated area burnt (ha)
Australian Capital Territory
94
157 000
New South Wales
2 500
1 464 000
Northern Territory
2 886
38 400 000
Queensland
2 778
8 000 000
South Australia
1 311
2 610 000
Tasmania
1 500
58 000
Victoria
3 000
1 300 000
Western Australia
11 515
15 545 000
Source: Ellis et al (2004)
Figure 6: Area of forest in Australia burned due to wildfire and fuel reduction burns, 1995–2004
5000000 4500000
Hectares burnt
4000000 3500000 3000000 W ildfires Fuel reduction burns
2500000 2000000 1500000 1000000 500000 0 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 Year
Source: AGO (2005)
To illustrate some of the impacts of fire, examples of different fire regimes are given from the forests and woodland of the southern Australia and the tropical savannas. South-eastern Australia has experienced several major bushfires in recent years, including the extensive alpine fires of 2003. Because such large alpine and subalpine areas were burnt in one event, this could have resulted in major impacts on plants and animals, including several nationally threatened fauna species and rare plants and sensitive vegetation communities (such as peat bogs). Additional impacts can result from the thousands of kilometres of heavyvehicle tracks and fire lines that create opportunities for species invasion. While fires appear to result in significant change to landscapes in the higher rainfall parts of south-eastern Australia, there is evidence of irregular but episodic fires in both the historical records and in the patterns of vegetation responses to fire (for example, fire sensitive ash species Eucalyptus regnans and Eucalyptus delegatensis). There is a strong tendency for major fires to be associated with periods of below average rainfall (for example, 1939, 1983 and 2003). One response arising from these fires has been the increased prescription burning for fuel reduction and for asset protection. Despite various prescriptions for burning regimes, the use and management of fire across Australia’s diverse ecosystems will remain controversial. Therefore the most substantive issues are not the area burnt but the area subjected to welldeveloped fire management plans that include biodiversity conservation objectives, and the need for monitoring and reporting systems to track biodiversity responses. An example is in
parks in the Northern Territory, which have fire monitoring programmes that are designed to measure biodiversity trends (Edwards et al 2003). In much of the northern savannas, there is now a higher incidence of extensive, hot, late, dry season fires, with marked environmental costs. These fires are of much higher intensity and of greater scale than traditional burning practices by Indigenous peoples. Instead of a patchwork of burnt and unburnt country, important habitat refuges are easily lost leading to a loss of regional biodiversity. Table 11: Approximate fire-affected areas across Australia, 1997–2003 Year
Area (million hectares)
Percentage of total land area fire affected
Percentage of fire affected area that is tropical savanna1
1997
48.3
6.3
86
1998
26.3
3.4
92
1999
60.0
7.8
86
2000
71.5
9.3
65
2001
80.1
10.4
84
2002
63.8
8.3
63
2003
31.6
4.1
85
1
Defined by the Department of Land Information, for the purposes of monitoring fire-affected areas, as
being the area north of 21°S and east of 120°E. Source: Western Australian Department of Land Information (2004)
In contrast, in the wet tropical environments with an average of more than 1500 millimeters of rainfall each year—on Cape York Peninsula and in the Wet Tropics bioregions—massive habitat changes are still occurring due to the decreasing incidence of fire, largely caused by fuel removal by cows. Grasslands have mostly disappeared under shrubs and trees, and wet sclerophyll communities have been significantly invaded by rainforest causing the loss of habitat for many species (Stanton 1995). The reintroduction of regular fire into these systems, and possibly hotter fires to ensure penetration, is required. In the drier 500–800 millimetre rainfall belt, some Acacia communities such as Brigalow (Acacia harpophylla), Gidgee (Acacia cambagei) and the botanically diverse vine thickets are sensitive to fire. The introduction of exotic pasture species such as Buffel Grass ((Cenchrus cillaris) can carry fire into these fire retardant but fire sensitive communities, causing their loss. Likewise, introduced Gamba Grass (Andropogon gayanus), which grows to four metres high, in the Top End has caused such fuel loads that even the structure of eucalypt woodlands may be threatened (Bowman 1999; CSIRO 2002).
In some agricultural and pastoral regions, fire has been excluded for social and economic reasons. There often is a reticence by the community to allow the use of fire because of threats to safety and property, and because the short-term loss of pasture is considered economically undesirable. In places this has led to invasion by woody shrubs, which causes the loss of ground cover and sometimes creates conditions where controlled use of fire as a management tool to control woody shrubs cannot be used due to the lack of grassy biomass (fuel) in the ground layer (Noble et al 1990). Fire was recognised in 1999 as a main threatening process for many rare, vulnerable and endangered Australian birds (Woinarski 1999) and this situation has not improved. The long history of the withdrawal of traditional burning practices has allowed radical changes to occur to the structure and floristics of many habitats. In some places, the return to traditional burning is not possible. In contrast, in large parts of northern Australia and across our rangelands, the adoption of burning practices based on the combined experience of traditional ‘grass burn’ and scientific knowledge is essential to achieve sustainable management for biodiversity (Latz 1995). The adoption of appropriate fire regimes could be one of the most cost-effective tools for biodiversity management across large parts of Australia Williams et al (2001) identified a tension between management of fire for biodiversity protection versus other management objectives in much of Australia. Some progress has been made since SoE2001 towards resolving this dilemma, with the publication of several guidelines based on research on the fire ecology of a range of species. The application of a technical understanding of fire regimes and their impacts on different ecosystems to protect biodiversity as part of ongoing land management remains a key challenge. This will involve much greater investment in research and in community understanding of appropriate fire regimes than currently exists. Finally, fire frequency and intensity, and the probability of uncontrollable fires, are likely to change significantly with climate change (see below).
Grazing Grazing affects biodiversity in a range of ways, including direct removal of some species, changes in the relative proportions and mixtures of species in ecosystems such as grasslands, shrublands and woodlands, alteration to habitat in mid-and lower storeys of forests and grasslands, altered fire regimes, and impacts on soil structure and water infiltration. Total grazing pressure is considered to be the most significant threat to a range of biodiversity elements, including threatened ecosystems across Australia (Table 4). Very large reductions in extent of all native grasslands have occurred since 1750 (Table 4).
Table 12: Area of pre-1750 and extant natural temperate grasslands Bioregion
Pre-1750 (ha)
Extant (ha)
Proportion remaining (%)
Brigalow Belt South
270 000
25 000
9.26
Flinders Lofty Block
1 500 000
5 000
0.33
Murray-Darling Depression
440 460
1 244
0.28
Riverina
2 750 000
26 871
0.98
South East Coastal Plain
60 000
25
0.04
South Eastern Highlands
450 000
. ERIN 2005, ‘Analysis of forest in the intensive landuse zone’, unpublished data from the Environmental Resource Information Network, Department of the Environment and Heritage, source of data AGO Version 1, July 2005, NCAS, DEH/AGO, Canberra. Fensham R 2006, ‘Spring wetlands of the Great Artesian Basin – unique environments’, paper for the 2006 Australian State of the Environment Committee, Department of Environment and Heritage, Canberra, .
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